The present disclosure relates generally to aircraft sensing and/or display systems. The present disclosure more specifically relates to an apparatus and method for the detection and/or display of runways and/or runway features using radar.
Displays are used in head down display (HDD) systems, head up display (HUD) systems including but not limited to wearable displays such as helmet mounted display (HMD) systems. In aircraft applications, HUD and HDD systems advantageously display information from aircraft systems and sensors in a graphical and alphanumeric format. The display information can include an enhanced vision image from a camera or other imaging sensor (such as a visible light imaging sensor, infrared imaging sensor, millimeter wave radar imager, or combinations thereof) and/or a synthetic vision image from a synthetic vision computer in certain applications. The enhanced vision image can be merged with a synthetic vision image to provide a single image to the pilot. The image can further contain or be augmented by alphanumeric and iconic symbology that highlights or enhances the image content.
Enhanced flight vision systems (EFVSs) are often utilized to view the runway during the approach or landing phases. Infrared cameras and light sensors used by conventional enhanced vision systems can have a limited ability to penetrate certain challenging weather conditions, such as CAT III fog and heavy precipitation. For example, infrared-based systems can have difficulty detecting and displaying runways in low visibility conditions (e.g., under 300 feet runway visual range (RVR)).
Enhanced flight vision systems have been proposed which use radio frequency (RF) signals such as millimeter wave (mmW) radar and/or weather radar signals (X-band, K-band, etc.). RF signals are better able to penetrate challenging weather conditions. However, conventional use of RF signals often deliver images of lower resolution when compared to infrared-based cameras and light sensors. Various weather radar systems are described in the applications incorporated herein by reference.
FAA-certified enhanced flight vision systems can allow pilots landing under instrument flight rules to operate below certain specified altitudes during instrument approaches even when the airport environment is not visible. Conventional SVS cannot provide enhanced flight visibility, especially the capability to show a real world sensed image of the runway during an impending landing. Although SVS has been approved for flying an instrument approach procedure, SVS has not been approved for operations below authorized decision height (DH) or minimum descent altitude (MDA). The use of an integrity monitor for a SVS may allow for higher design assurance levels which could lead to the use of monitored SVS for lower landing minimum credit (e.g., would allow a pilot with a monitored SVS display system to land where a non-monitored SVS pilot would not be otherwise allowed to land due to the current low visibility or RVR restrictions). Accordingly, there have been proposals to provide a monitor for an SVS system based upon various instruments. The use of additional equipment to provide an integrity monitor for the SVS can add to the cost and weight of the aircraft.
Accordingly, there is a need for systems for and methods of detecting runway features using radar data and/or displaying images (e.g. runway features) derived from radar data. There is still a further need for systems for and methods of providing real time symbols or images derived from weather radar data. Yet further, there is a need for a HUD including runway symbology or icons derived from radar data. There is also a need for a system for and method of providing an integrity check for an SVS without use of additional systems. There is also a need for systems for and methods of detecting a runway or taxiway and its orientation in challenging weather conditions. There is also need to aid detection and display of runway features using weather radar.
It would be desirable to provide a system and/or method that provides one or more of these or other advantageous features. Other features and advantages will be made apparent from the present specification. The teachings disclosed extend to those embodiments which fall within the scope of the appended claims, regardless of whether they accomplish one or more of the aforementioned needs.